CXCR-4 surface overexpression on PB Inc⁺CD34⁺ cells is correlated with a decrease in the CXCR-4 intracellular pool and protein synthesis.

PB CD34⁺ cells were purified (A) without (Inc⁻) or (B) with (Inc⁺) overnight incubation on a plastic support. (C) PB mononuclear cells were treated with cycloheximide before overnight incubation and CD34⁺purification. We studied CXCR-4 expression at the surface by labeling cells with PE-conjugated anti-CXCR-4 mAbs. CXCR-4 expression within the cell was analyzed after saturation with unconjugated CXCR-4 mAbs, permeabilization, and labeling using PE-conjugated anti–CXCR-4 mAbs. Cytometry analysis was performed on the FSC/SSC gated population as indicated in Figure 1. The histogram represents 8000 to 10 000 events in the total ungated population. The isotyped matched negative controls are shown in the overlay (light lines). Data from at least 3 donors were analyzed, with similar results. Histograms from a typical donor are presented. The mean percentage and MFI of positive cells for CXCR-4 ± SD are shown for each histogram.